I'm picking that Laila Harre's appointment as leader of the Internet Party will be good for Internet-Mana, but the impact on this year's election will be determined by the relationship with Labour. If Internet-Mana do well this year, though, there might be an important shake-up that will strengthen the broad left in the longer term.

Laila's selection is shrewd of the Internet Party and good for Mana. Few people to the left of Labour have as much credibility. She won't be dismissed as a puppet of Kim Dotcom. She has a deep understanding of the way party-alliances work, which will probably make her more patient with the complexities of a merger.

Hone Harawira's seat looks more secure. There are noises coming from Labour that it won't try very hard in the Tai Tokerau. Matt McCarten is Laila Harre's oldest friend in politics and more likely to be loyal to her than the party he is now running. He won't fight for the North.

Though she is popular with a group of former Alliance activists who have spread out across the Internet party, Mana, the Greens and Labour, Bryce Edwards linked to an hilarious tweet that asked, 'what was the point of principle that caused Sue Bradford to leave Mana and Laila Harre to join?'

The answer may be a thread that runs through 25 years of left-wing politics - back to 1989 when Sue Bradford stormed out of the New Labour Party, which Laila helped to set up. Despite being two of the most prominent women to the left of Labour, the two have not been seen on the same platform since. Sue represents a more reactionary form of the left, defined by what it's opposed to. Laila's is a more principled pursuit of purist policy outcomes.

However, purism has never won Laila an election in her life. In 2002 she couldn’t beat Lyn Pillay in Waitakere. As leader of the Alliance she won 1.2% nationally (although at a time when Labour was polling 50% and the Alliance brand was mortally ruined.) The closest analogue is Don Brash taking over Act, which also generated tons of media coverage but failed to add a list MP to the party's constituency.

If some votes Internet-Mana receive come from Labour and the Greens to Internet-Mana, the overall balance of parliament this year will be undisturbed.

But the left could grow over the next three years from the emergence of a genuine non-Labour party of the left. There are plenty of activists who value the Greens' ecological concerns but who are more attracted by its socialism (we can call this faction of the Greens "Russel Norman.") Some potential supporters have been unhappily in Labour, where they've never been accepting of Labour's social democracy. They will feel more at home in a socialist party.

I expect Laila to attack Labour from the left, or at least noisily differentiate her party, making Labour look more moderate and electable if it ignores the new party and focuses on its core priorities of jobs, wages and security. Helen Clark became successful in the 1990s only when she learned to ignore the Alliance.

But if Labour feels pressured to respond to a more militant economy message, and drawn into more protest and lifestyle issues, National will pounce - either accusing the left of being divided and in disarray, or of moving to the 'far left'. By absorbing some activists, a new left party is likely over time to diminish the internal pressure on Labour to fall into the trap.

Im not saying its bad for Labour to be left wing. I'm saying they don't need to be as left wing as Laila who would never call herself a social democrat. There's a proud tradition of social democratic Labour parties (Gillard and Rudd in Australia, Milliband and Neil Kinnock in the UK etc). None of these Labour parties looked like a bunch of Tories. There's room for us all on the left, is my point.

Hi Draco - actually Helen Clark became successful from the '96 campaign because she stopped fighting the Alliance and focused on National - that's the point. The agreement that you're linking to was signed and negotiated after the '99 election. I know because I was a press secretary at the time.